Search results for "Reverse"

Reversed phase liquid chromatography for the enantioseparation of local anaesthetics in polysaccharide-based stationary phases. Application to biodeg…

2020

[EN] A comprehensive study on the chiral separation of bupivacaine, mepivacaine, prilocaine and propanocaine with eight commercial polysaccharide-based chiral stationary phases (CSPs) in reversed phase conditions compatible with MS detection is performed. Methanol and acetonitrile are used as organic modifiers. Retention and resolution values obtained for each compound in the different CSPs and mobile phases are compared. The polysaccharide-based CSPs tested present different enantioselectivity towards the analytes. From the results, the experimental conditions for determining the enantiomers of bupivacaine, mepivacaine, prilocaine and propanocaine in saline aqueous samples using MS detecti…

Cast multibilayer films from polymerizable lipids

1987

Novel solutions for closed-loop Reverse Electrodialysis: thermodynamic characterisation and perspective analysis

2019

Abstract Closed-loop Reverse Electrodialysis is a novel technology to directly convert low-grade heat into electricity. It consists of a reverse electrodialysis (RED) unit where electricity is produced exploiting the salinity gradient between two salt-water solutions, coupled with a regeneration unit where waste-heat is used to treat the solutions exiting from the RED unit and restore their initial composition. One of the most important advantages of closed-loop systems compared to the open systems is the possibility to select ad-hoc salt solutions to achieve high efficiencies. Therefore, the properties of the salt solutions are essential to assess the performance of the energy generation a…

PROGETTAZIONE PER ADDITIVE MANUFACTURING DI ORTESI DI GOMITO PERSONALIZZATE E SVILUPPO DI MODELLO PARAMETRICO BASATO SU ALGORITMI GENERATIVI

Machine learning of reverse transcription signatures of variegated polymerases allows mapping and discrimination of methylated purines in limited tra…

2020

AbstractReverse transcription (RT) of RNA templates containing RNA modifications leads to synthesis of cDNA containing information on the modification in the form of misincorporation, arrest, or nucleotide skipping events. A compilation of such events from multiple cDNAs represents an RT-signature that is typical for a given modification, but, as we show here, depends also on the reverse transcriptase enzyme. A comparison of 13 different enzymes revealed a range of RT-signatures, with individual enzymes exhibiting average arrest rates between 20 and 75%, as well as average misincorporation rates between 30 and 75% in the read-through cDNA. Using RT-signatures from individual enzymes to trai…

The reverse transcription signature of N-1-methyladenosine in RNA-Seq is sequence dependent

2015

The combination of Reverse Transcription (RT) and high-throughput sequencing has emerged as a powerful combination to detect modified nucleotides in RNA via analysis of either abortive RT-products or of the incorporation of mismatched dNTPs into cDNA. Here we simultaneously analyze both parameters in detail with respect to the occurrence of N-1-methyladenosine (m1A) in the template RNA. This naturally occurring modification is associated with structural effects, but it is also known as a mediator of antibiotic resistance in ribosomal RNA. In structural probing experiments with dimethylsulfate, m1A is routinely detected by RT-arrest. A specifically developed RNA-Seq protocol was tailored to …

IL-21 regulates experimental colitis by modulating the balance between Treg and Th17 cells

2007

Regulatory T (T(reg)) cells play a key role in the maintenance of the immune system homeostasis. T(reg) cells can be generated in the periphery under control of TGF-beta, a cytokine involved in the negative control of the immune system. However, TGF-beta cooperates with IL-6 in the generation of Th17 cells, a novel class of effector cells involved in numerous inflammatory diseases, including colitis. Therefore, TGF-beta emerges as a mediator of both anti-inflammatory and pro-inflammatory processes, depending on the local cytokine milieu. Here we demonstrate that IL-21, a type-1 cytokine produced by T cells and involved in the pathogenesis of immune-mediated diseases, prevents the TGF-beta-d…

Performance of amines as silanol suppressors in reversed-phase liquid chromatography

2016

In reversed-phase liquid chromatography, cationic basic compounds yield broad and asymmetrical peaks, as a result of their ionic interaction with the anionic free silanol groups present in the silica-based stationary phases (commonly derivatised with C18 groups). A simple way to improve the peak shape is the addition to the hydro-organic mobile phase of a reagent (usually called additive) with cationic character. This associates with the stationary phase to prevent the access of analytes to the free silanol groups. Cationic additives may interact electrostatically with the anionic silanols. The hydrophobic region of the additive may also associate with the alkyl chains bound to the stationa…

Endometrial receptivity revisited: endometrial transcriptome adjusted for tissue cellular heterogeneity

2018

Study question Does cellular composition of the endometrial biopsy affect the gene expression profile of endometrial whole-tissue samples? Summary answer The differences in epithelial and stromal cell proportions in endometrial biopsies modify the whole-tissue gene expression profiles and affect the results of differential expression analyses. What is already known Each cell type has its unique gene expression profile. The proportions of epithelial and stromal cells vary in endometrial tissue during the menstrual cycle, along with individual and technical variation due to the method and tools used to obtain the tissue biopsy. Study design, size, duration Using cell-population specific trans…

β-Adrenoceptor stimulation up-regulates phosphodiesterase 4 activity and reduces prostaglandin E 2 -inhibitory effects in human neutrophils

2000

Human neutrophils were treated for 4 h with a combination of salbutamol (1 µM), a β2-adrenoceptor agonist, and rolipram (30 µM), a selective phosphodiesterase 4 inhibitor, to investigate whether this treatment produces up-regulation of phosphodiesterase activity with functional consequences. Anion-exchange chromatography coupled with the use of selective activators and inhibitors demonstrated that a phosphodiesterase activity with characteristics of the isoenzyme type 4 was increased in drug-treated cells. Kinetic analysis showed a ~1.5-fold increase in V max without alteration of K m values. The augmented phosphodiesterase activity in drug-treated cells was abolished by actinomycin D. Cycl…